초록

GSM is the most widely deployed 2nd generation digital cellular standard, with over 2 billion subscribers in some 213 countries and adding about 1000 new users per minute! Originally developed in the 1980s, and first deployed in 1991, GSM is a TDMA+FDMA system, providing wide area voice communications using 200 KHz carriers. Subsequently, GSM evolved into a 2.5G standard with the introduction of packet data transmission technology (GPRS) and higher data rates via higher order modulation schemes (EDGE). More recently, GERAN standards organization has been evolving further to coexist with and provide comparable services to 3G technologies. In this paper, we provide an over view of evolution of GSM technology and also the framework of 4G technology that will provide access to wide range of telecommunication services, including advanced mobile services, supported by mobile and fixed networks, which are increasingly packet based, along with a support for low to high mobility applications and wide range of data rates, in accordance with service demands in multiuser environment.